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A TEXTBOOK OF PHYSIOLOGY 



blood-receiver F is constructed of three bulbs, so as to prevent the 

 blood frothing over into B during the extraction of the gases. To 

 either end of F is fixed a piece of thick, small-bored pressure tubing 

 provided with a clip. 



In using the pump, the blood-receiver F is placed in the position 

 indicated by the dotted line. A is raised, and B is put in connection 

 with F, and F is filled with mercury. The screw clip on the rubber 



FIG. 132. HILL'S BLOOD-GAS PUMP. 



tube at the upper end of F is then closed, and A lowered until F is 

 exhausted, except for 2 or 3 c.c. of mercury which are purposely left 

 within. The screw clip on the lower end of F is next closed, and F is 

 then detached from the pump and weighed. Blood is collected in 

 this evacuated receiver, which is then connected to the apparatus, 

 and the gases pumped off into the eudiometer H, where they are 

 analyzed. The amount of C0 2 is determined by introducing 20 per 

 cent. KOH, the oxygen by introducing a solution of pyrogallic acid. 

 The relative proportions of the gases are shown in Fig. 133. The 

 remainder is nitrogen. 





